Your link is dead. Please post the image as an attachment, or host it elsewhere, so we can have a look at it.
[edit] Sorry, it was net issues on my part.

It looks like pretty straightforward brush painting without any special techniques. Although the difference in quality between the architecture and the "foreground squiggles" is suspect; it may be stolen concept art that was painted over to hide the artists signature.

Regardless, it was probably painted in photoshop. To do this, get a tablet and start learning the basics of painting.